Hot water heat zone valves

[suitcase_sally]

I'm posting this on this forum because more people view this one than do the Shop Talk forum. Feel free to move it if necessary..

I have a two story home with baseboard heat. There are three zone valves, one for the main floor and two for the upstairs (one in master bedroom and one for the other rooms). I have the thermometer in the master bedroom turned as far back as it will go (50). When the furnace calls for heat on the main floor I get heat in the master bedroom. I wonder if the zone valve is stuck open, and if so, how do I get it to close? Or is there some other problem?

[hunter63]

Sounds like it is stuck open. Check on the side of the zone valve, should be a "manual" lever to open or close it. Most valves are made to fail in the open position.
This will give you temp control for now.


Next check voltage at the T-stat with a volt meter, should show 24 volts across the t-stat leads when turned down (50 degrees) or "open", nothing when turned up (80 degrees) or "closed".
If you do have voltage, then it could be a broken wire at the t-stat, transformer, bad motor on valve, lots of things. Some valves, you can replace just the motor, some not.


This might be a big job, depending on the install.
Does it have manual valves on either side if the zone valve?
Might have to drain the boiler to replace it, if you can't isolate the zone valve.
Unscrew or unsolder the valve and replace it.
Good luck

[dagwood]

The electric motor on the valves are known for being the likely culprit. They are easy to change out without replacing the entire valve. (At least mine have been )

[suitcase_sally]

I will check out the pertinent info and get back. Thanks!

[suitcase_sally]

Well, being that I'm electronically challenged this looks like a job for Super Hubby. All I found out was that it's a Honeywell motorized unit. It has a little moveable arm-like thingy on top but nothing happened when I moved it.

[hunter63]

That means the it is stuck open, you can try tapping on it, but it sounds like the valve body is stuck open.
If it was stuck closed, you can use that lever to open it, there is a little notch for it to lock into in the open position.
Does it have manual valves on either side of it?

[suitcase_sally]

I only see one of the manual arms on it and it is in the open position (locked). I can move it to the other position but I can't tell if anything is happening internally. Is it safe to leave it in this position (closed) long enough to see if the heat turns off in that room?

[hunter63]

Yes, it won't hurt anything, did you try tapping on it?

I just had a job replacing a zone valve, doing the same thing as yours, too much heat.
By tapping on it , got it to work at least long enough to run and get a part to fix it.
It will probably stick again so don't think that you fixed it if it does work temporally.

By the by, if you do need to replace it, you might just need top shut down the boiler, drain down some water to get it out of the system. Then replace the valve. You shouldn't need to drain the whole system.
Were talking second floor here, the job I had was in the basement, had to drain the whole thing.

Good thing we caught it before it was too cold.
Good luck